This invention disclosure relates to containers and particularly to molded plastic containers having permanently attached snap rings and removable lids.
It is well known that paint is typically sold in metal one gallon cans which are generally cylindrical in shape. Welded metal cans have a ring structure with annular grooves added to the top of the can to receive a lid in such a way as to provide an air-tight seal, to permit the lid to be pried off with a tool, and to permit the lid to be reapplied to the container.
Containers made from high density plastics such as polyethylene have numerous advantages over metal containers; for example, plastic containers are far less susceptible to denting and are virtually rust proof. Therefore, it would be desirable to replace metal cans with plastic containers. However, plastic containers are typically not cylindrical and are incompatible with the machinery currently used to fill and seal metal cans.
The overall objective of the present invention is to provide a plastic container construction consisting of the combination of an open-top container, a snap ring permanently affixed to the top edge of the container, and a removable lid, which provides durability, excellent sealing qualities and, if desired, can be made in a shape with emulates traditional metal paint can so as to be compatible with handling machinery for traditional metal paint cans.
In particular, an objective of the present invention is to provide a plastic container structure in which an improved seal is provided between the lid and a snap ring structure which is tolerant of rough handling and lateral loading but which readily admits of the use of a simple tool such as a screwdriver to pry the lid from the snap ring. Other objectives include the provision of an internal brush ring integral with the snap ring, and stackability features for the cans and all of the related components, both alone and in combination.
In general these advantages are achieved through the provision of a snap ring structure which is adapted to be affixed to the top edge of an open top container which is preferably but not necessarily cylindrical; i.e., the invention works with tapered containers and non-round containers. As stated above, the preferred shape for the container is cylindrical but the features and advantages of the invention are applicable to other shapes. The snap ring structure is xe2x80x9creentrantxe2x80x9d in design; i.e., it exhibits a depressed center structure which, in general, lies below a plane defined by the top edge of the container. As hereinafter described in detail, the snap ring defines a peripheral section defining an inverted unshaped groove for receiving the top edge of the container. Inboard there is a reentrant section which forms an annular depression lying mostly or entirely below the top plane. Inboard of that is an upstanding annulus which is contiguous with the annular depression to provide a primary seal and lock element when combined with a suitable lid. The combination further comprises a lid having an inverted U-shaped section which receives the upstanding annulus of the snap ring and conforms in sealing engagement with both the radially inner and outer exterior surfaces of the annulus. Finally the lid structure has an integral pry ring which, when the lid is applied to the snap ring, lies within the upper portion of the annular depression of the snap ring to permit the introduction of a tool to pry the lid from the snap ring.
Further objectives and advantages are achieved in optional features of the present invention described in the following specification with respect to several illustrative embodiments of the invention. These advantages include a novel brush wiper ring which is integral with the inner edge of the snap ring so as to permit the end user to wipe excess paint from a brush which has been dipped into the contents of the container. The preferred wiper ring is formed with a plurality of circumferentially arranged apertures to permit paint to be poured therethrough.
As will also be apparent from the following description of the preferred embodiments, the annular lock ring of the snap ring structure can be formed as either a solid single leg upstanding structure or as an inverted U-shaped loop structure having inner and outer legs which are resiliently displaceable toward and away from one another. The latter structure provides additional seal area and additional resistence to leakage due to rough handling.
The features and advantages of the present invention will be best understood by reference to the following description of the specific and illustrative embodiments of the invention.
Other objects, advantages and applications of the present invention will become apparent to those skilled in the art when the following description of the best mode contemplated for practicing the invention is read in conjunction with the accompanying drawings.